The following steps are now automated by the oscar_fork_app management
command. They’re explained in detail so you get an idea of what’s going on.
But there’s no need to do this manually anymore! More information is
available in /topics/customisation#fork-the-oscar-app.

If two models with the same name are declared within an app, Django will only
use the first one. That means that if you wish to customise Oscar’s models, you
must declare your custom ones before importing Oscar’s models for that app.

You have to copy the migrations directory from oscar/apps/order and put
it into your order app. Detailed instructions are available in
How to customise models.

When you replace one of Oscar’s apps with a local one, Django admin integration
is lost. If you’d like to use it, you need to create an admin.py and import
the core app’s admin.py (which will run the register code):